Weld Quiz
1. What is heat input in arc welding
Arc voltage * Arc current/ Welding speed (V I/S).
2.What type of power source characteristics are used for SMAW
Constant current or drooping characteristics
3.What polarity is required for GTAW
DCEN
4.What polarity is used for GMAW and SAW
DCEP
5.What type of power source characteristics is used for GMAW,SAW.
Constant voltage or flat
6. What is fusion welding
Base metals and filler melt and solidify to form a weld
7.What is Pressure welding
Pressure,or heat and pressure or fusion under pressure forms a weld.
8.What is autogenous welding
No addition of filler to form joint
9.What is homogenous welding
Matching composition filler as that of base metals is used to form weld
10.What is heterogenous welding
Base metals,filler are of different compositions
11.What are the types of power sources for SMAW
Transformers(AC),Rectifiers(DC),Motor generators(DC)
12.What current range is used in SMAW
25-600 amps
13.What is the range of open circuit voltage in SMAW
50-100 volts
14.What is the range of arc voltage in SMAW
16-40 volts
15.What is the advantage of using killed steel for SMAW electrodes
Elimination of porosity in welds due to absence of oxygen
16.What are the high deposition rate arc welding processes
GMAW,SAW,Multi wire ESW
17.Which electrodes are commonly used for all position structural welding
E6012,E6013,E7018
18.What is plasma
Ionised column where electrons and ions move freely from cathode and anode respectively.
19.What are the two types of plasma processes
Transferred arc,Non-transferred arc
20.What is energy density
Concentration of heat per unit area which varies significantly from process to process.Unit is watts per sq.cm
21.Give example for very less energy density process
Oxy acetylene welding
22.What is LASER
Light Amplification by Stimulated Emission of Radiation
23.What is the mechanism for heat input in EBW
High velocity focussed beam of electrons bombardment on base metals
24.How heat is produced in LASER
Photon coherent focussed beam impinging on base metals
25. What are the important welding variables in SAW
a) Voltage b)Current C)Welding speed d)Wire feed rate e)Flux depth f)Electrode extension
26)What is basicity index for fluxes
Ratio of basic oxides to acidic oxides
27)Which flux is used in SAW for critical applications
Basic flux( Basicity index greater than 1)
28)What is the range of deposition rate in SMAW
3 to 6 kg/hr
29. What are the shielding gases used in GMAW
carbon dioxide,Argon,Argon +carbon dioxide and other gas mixtures recommended for specific metals
30.What welding variables are important in GMAW
Current,Voltage,Wire feed rate,Wire extension,Gas flow rate,Gas pressure,Type of gas,Welding speed,Pulsing parameters
31.What are the processes used for narrow gap welding
Narrow gap TIG,Narrow gap MIG,Narrow gap SAW
31.When do you use strip cladding process
Over laying of desired metal on substrate
32.What are the two types of FCAW
a)Self shielded b)Gas assisted
33.Where is FCAW used in industries
Structural welding, Ship building,
34.What are the types of EGW for vertical plate welding
a) Consumable wire b)Consumable guide
35.What are the variations for ESW
a) Vertical welding processes)Shell welding process
36.What is duty cycle of power source
%duty cycle = current on time/(current on time +current off time)
37.How is capacity of SMAW power source indicated
Current at 60 % duty cycle
38.What is hot wire GTAW
The filler wire continuously enters weld pool after prior heating
with special heating device provided in the total system.
39.What is pulsed GTAW
The electric circuit provides Peak current and background in pulses at a particular frequency.This facilitates control of heat input.
40.What are the variations in GMAW
Arc pulsing or wire pulsing
41.What is synergic power source
Arc pulsing adjusted automatically and no need of adjusting individually parameters
41.What is micro plasma
The current levels are very low in magnitude.
42.What are the two types of plasma arc
Transferred and non transferred arc
43.When transferred arc plasma is useful
Welding applications
44.What applications non transferred arc plasma is useful
Cutting and non conducting materials
45.What is the use of key hole plasma welding
Single pass full penetration welding in flat position
46.What is plasma powder fusion
Normally used to melt and fuse hard facing alloy powders by plasma arc.
47.Which process is ideal for cutting large thickness aluminium,stainless steel,titanium
Plasma cutting system
48.Which process is good for ceramic spraying
Plasma spraying with non transferred arc
49.What are the important variables in EBW
Beam current,Beam Voltage,Welding speed
50. What are the two types of EBW machines
60 kv,(low kv),150kv(high kv)
51.What capacity machines are generally available for EBW.
3kW to 100 kW
52. Indicate range of beam voltage and beam current inEBW
30 kV to 200kV and 50 milli amps to 1000milli amps.respectively.
53.What welding speeds are possible in EBW
Welding speeds can go as high as 30 mm /sec depending on thickness and metal.
54.What is the depth to width ratio for EB weld
20:1
55.What is the advantage of EB for hole making
Very fine holes in critical materials with close proximity and precision.
56.What type of joints are possible in EBW
Butt,Lap,T joints
57.What are the various processes in LASER material processing.
Welding,drilling,cutting,hardening,alloying,trimming,engraving
58. What are the equipment commercially available for LASER
Solid state and gaseous LASERS of different kW ratings
59.What variants are possible in EBW
Vacuum chamber of different levels(soft,hard),Out of vacuum,in situ vacuum.
60.When EBW and LASER are useful
Very challenging applications in aero space,nuclear,defence,and some times for typical mass production applications.
61.What is the order of cost of EBW,LASER equipment
Even smallest capacity machines are very costly and the initial investment to be justified by the need considering applications.
62.What are the advantages for augmented LASER.
TIG assisted LASER will improve capacity for typical applications.
63.What is the typical beam size for EBW.
0.5 mm
64.What is the order of beam size for LASER
0.1mm
65.Indicate Resistance welding processes for butt and lap joints.
Butt joints:Upset butt and Flash butt ;Lap joints :Spot,seam,projection
66. How is heat input in joules calculated in RW
product of square of current,resistance,weld time
67.Specify Electrode materials for resistance welding.
Pure copper,chromium copper, Beryllium copper,cadmium copper
68.What are the important parameters for resistance spot welding
current,load,squeeze time,weld time,hold time,off time.
69.What are various types of spot welding machines
1.Rocker arm2.Pneumatic 3.Hydraulic4.Robotic
70.Where is spot welding applied in mass production
Sheet metal fabrication :Automotives,Electrical,Domestic
71.Is dissimilar thickness sheet metals welding possible.
Yes.Selecting proper electrode tip diameters to achieve heat balance.
72.What materials can be welded by spot welding
Steels,stainless steels,aluminium,titanium,coated steels etc
73.What is spot in spot welding
Nugget solidified in between two sheets in lap joint.
74.What is micro spot welding
Bench-type small spot welding machine to weld foils and small diameter wires.
75.What is pitch distance in spot welding
Centre distance between two adjacent spots.
76.How is capacity of spot welder specified
KVA rating at 50% duty cycle
77.Is spot welding applied for leak tight joints
No.Spots are separated as per pitch distance
78.How is the quality ensured for spot welds
In process quality monitoring system with the machine
79.What is Projection welding
A projection of specific geometry is incorporated in one of the sheets to achieve energy concentration . Flat electrodes are used in the press type machine.
80.What is done for dissimilar thickness welding in projection welding.
Projection is given on the thicker member to achieve heat balance.
81.How is projection made
Natural projection(wire over wire),Machined,Formed.
82.Is simultaneous welds possible
Multiple welds can be made by incorporating projections wherever weld has to be made
83.What are the typical applications of projections
Valve seats,Door handles,Wire meshes,Floor grills,Dissimilar thicknesses,
84.What capacity machines generally are heavy duty.
Starting from 100 KVA onwards are used for delivering higher currents for each of projection or for ring projections.
85.Is full automation possible.
Yes.With in feed ,welding station ,out feed ,machines can take care of continuous production.
86.What mass production applications currently employ projection welding
Automotives,Electrical,Domestic appliances,Power plant equipment,Furniture,etc.
87.What to be done when dissimilar thicknesses to be welded by projection welding.
Projection of suitable geometry to be on the larger thickness.
88.What to be done when welding dissimilar thermal conductivity metals.
Projection should be on higher thermal conductivity metal
89.What is seam welding.
Over lapping spots are made for leak tight joints for lap joints.
90.What type of electrodes are required for continuous seam welding.
Circular electrodes are used to weld in sheet metal fabrication.
91.How to get over lapped spots or nuggets
By adjusting the ratio of current on to current off time.
92.What are the typical applications for seam welding
Petrol tanks,Oil drums and other leak tight joints.
93.What various types of machines are employed for mass production
Portable seam welders,Machines with circular electrodes perpendicular to arms,Machines with circular electrodes parallel to arms.
94.What are the electrode materials for seam welding
chromium copper alloy.
95.What cooling system is used for electrodes
Flooded cooling
96.What are the resistance welding processes for butt joints
Upset butt,and Flash butt welding processes.
97.What are the typical applications for upset butt welding.
wire to wire,rod to rod,ring welds,strip to strip,tube to tube
98.What are the parameters for upset butt
Upset pressure,Current,Weld time
99.What are the parameters for Flash butt welding
Flashing voltage,Flashing velocity,Clamping pressure,Die opening,
upset pressure,upset time,Preheat cycle,post heat cycle
100.What are the typical applications
Tube to tube,billet to billets,rail joints,pipe to pipe,wheel rims,dissimilar metal welds,ring welds,tools(same cross section area required for both members to be welded)
101.What are other Resistance welding processes employed
High frequency butt seam welding,Foil butt seam welding,Mash seam welding
102.Indicate various solid phase welding processes
Ultrasonic welding,Explosive welding,Diffusion bonding,Friction welding,Friction surfacing,Friction stir welding ,Friction stud welding.
102.How metallic bonding achieved in Ultrasonic welding
Virgin metal surfaces come in contact with the help of load and lateral vibrations applied with ultra sonic frequency and amplitude.
103.What parameters are important for Explosive welding
Explosive type, stand off distance,(parallel configuration)plate angle (angular configuration)Detonation velocity,packing density
104.What are the applications for USW
Wire to wire,strip to strip,button to strip,wire to strip
105.What are the applications for EXW.
Dissimilar metal cladding,Tube to tube sheet welding,Transition joints
106.What are the requirements for diffusion bonding
Perefect cleaning and surface finish for metals,Pressure to achieve metallic contact,Diffusion time,Concentration gradient,Temperature for diffusion.
107.What are the typical applications for diffusion bonding
Challenging applications between metals to achieve drawing tolerances,dissimilar materials welds,Critical welds for defence and nuclear applications
108.How welds are obtained by friction welding
Friction between metals due to axial force and rotational speed causes heat and subsequent forging creates metallic bond.
109.What are the requirements for rotational friction welding .
The component kept in Chuck should be circular or rotational symmetry’s, and other component held in clamping can be of any cross section.
110.What is continuous drive friction welding
During heating phase the motor is continuously coupled to rotate the component in Chuck.
111.What is Inertia drive or flywheel friction welding
Fly wheel energy is consumed during welding and rotation stops at the completion of welding.
112.What are the important parameters for continuous drive friction welding
Rotational speed, heating time,heating pressure,upset pressure,upset time,burn off rate,heating loss,upset loss
113.What are the important applications for rotational friction welding
Dissimilar metal joints:Al to Cu,Al to Steels,Al to Stainless steel,Al to Titanium,Brass to steel,Low alloy steel to
Stainless,Titanium to Stainless steel,Copper to stainless steel.
Similar metals welding,Rod to rod,tube to tube,Rod to plate,Tube to plate type joints.
114.What advantages does FSW have over conventional welding?
Material does not melt when Friction Stir Welding.Many of the problems we associate with fusion welding are eliminated; since cooling from the liquid phase is avoided, there is no problem with porosity, solidification cracking, and liquid cracking .
Other advantages over fusion welding include:
• Good mechanical properties in the as welded condition
• Improved safety due to the absence of toxic fumes
• Elimination of spatter
• No consumables- conventional tool steel can weld over 3250′ (1000m) of
aluminum and no filler or gas shielding is required for aluminum
• A simple milling machine can easily be automated for FSW requiring less
set-up cost and less training
• Friction stir welding in all welding positions is possible because there is
no weld pool
• The finished weld generally has a good weld appearance which reduces the need for machining after welding
115.What are the disadvantages of FSW?
Disadvantages of Friction Stir Welding include:
• An exit hole is left when the tool is withdrawn
• Heavy down forces required for this process means heavy duty clamp-
ing is necessary to hold the plates together
• Less flexible than manual arc processes, and there is difficul-
ty with thickness variations and non-linear welds
• Often the traverse rate is slower than other fusion welding techniques
but this may be offset if fewer welding passes are required
• Less efficient when welding steels and stainless steels because the tool materials wear rapidly and debris from
the tool can frequently be found inside the weld.
115.What are typical industrial applications for FSW.
Automobiles ( Aluminium sheet metal fabrication),Dissimilar metals welding (Lap joints-aluminium to copper),Ship building,Aero space,Defence equipment
[116]What are some of the applications with aluminium alloys by FSR in automobiles.
Application
Inner and outer body panels
General Structure Components
Extrusions
Luggage racks, Air deflections
Space tire career parts Bumper components Ace bars Reinforcements
Brackets Seats
Shells
Head rest bars Tracks
Load floors Wheels Suspension parts Drive shaft
Drive shaft yokes
Engine accessory, brackets and mounts
Sub – frames and engine cradles
Miscellaneous
Radiator, heater and evaporator fins
Condenser tubes Condenser and radiator fins
Aluminum Alloys
2008, 2010, 2036, 3004, 5052, 5182, 5754, 6009, 6010, 6016, 6022, 6111
6005, 6005A, 6009, 6061
6063, 6062, 7005 6463
6061
5052, 6009
6009, 6061, 7003, 7004, 7021, 7029
6009, 7021
7036, 6010
7116, 7129
6010, 5182, 5754, 6009
2036, 5182, 5754, 6009
5454, 6061, A356.0
6061 (forging)
6061 (tube), aluminum metal matrix alloys
6061 (forging and impact extrusions)
5454, 5754
5454, 5754, 6061, 6063
3005
3102 7072
116.What are the requirements for mechatrode tool materials.
High temperature strength,hardness retention under dynamic loading conditions.
117.Specify some tool materials for FSW.
High speed steels,CBN
118.Why tool geometry is very important for FSW.
Stirring of weld and consolidation of weld depends on tool tip profile and geometry.
119.Can dissimilar metals be welded by FSW.
Many combinations can be tried,Metallurgical considerations may limit some metal combinations.
120.Is contour welding possible by FSW
yes.Robotic FSW systems can be employed to weld different contours.
121.What are other FSW processes
Friction stir spot,Friction surfacing,Multi stir,double side,twin stir,tandem,staggered etc.
122.Match the following
A. Electron beam welding. A.Photons
B.Friction stir welding. B.Mechatrode
C.LASER beam. C.Electrons
D.Ultrasonic welding. D.Sonotrode
Ans. A-C,B-B,C-A,D-D.
123. Match the following
A. Explosive welding A.Metallic jet
B.Diffusion bonding B.Fusion welding
C.GMAW C.Metallic bond
D. GTAW D.Non consumable electrode
Ans A-A,B-C,C-B,D-D.
124.Match the following
A Rotational speed A Ultrasonic welding
B Amplitude B Friction welding
C Explosive type C Diffusion bonding
D Temperature D Explosive welding
Ans
A-B,B-A,C-D,D-C
125.Match the following
A Electrode dressing A GMAW
B Flux depth B GTAW
C Globular transfer C SAW
D Neutral flame D Oxy acetylene welding
Ans
A-B,B-C,C-A,D-D
Welding Education and training
126. What are the processes under fusion under pressure
Resistance spot,seam,projection welding
127. What are the processes by solid state in resistance welding
Upset and flash butt welding
128. What is homogenous welding.
Composition , point to point in welded joint is same because of using
matching composition filler irrespective of process used.